A typical open end spinning machine, such as the AUTOCORO.RTM. rotor spinning machine available from Schlafhorst having an office in Charlotte, N.C., includes a series of individual open end spinning positions on both sides of an elongate machine frame. At each spinning position, sliver is drawn from a supply can and into a rotor or open end spinning area. The spun yarn is engaged and moved by a rotating take-up shaft and cooperating cot, and is wound by a drive roll to form a conical yarn package.
The spinning positions on each side of the open end spinning machine share several common operating components. Among the common components is a rotating take-up shaft. At each spinning position, the take-up shaft has an enlarged diameter area for engaging and advancing yarn from the open end spinning area. The advancing yarn is typically directed in a reciprocal motion back and forth over the enlarged diameter area to more evenly distribute wear.
One type of conventional open end spinning machine produces conical yarn packages, and, accordingly, includes a mechanism for maintaining uniform tension of the yarn, as well as a traverse bar for directing the advancing yarn in the reciprocating motion across the enlarged area of the take-up shaft. Another common conventional spinning machine produces cylindrical yarn packages, and, hence, does not have the tension controlling mechanism as in the machine for making conical yarn packages.
When a yarn parts on an open end spinning machine, such as downstream from the take-up shaft, it is likely to wrap around and form an entangled mass, that is, a yarn lap, on the enlarged diameter area of the take-up shaft. The yarn lap forms in the time before the movement of the yarn is fully ceased as caused by operation of a stop motion. Due to the loss in production time that would result if the common take-up shaft were stopped to remove a yarn lap at only a single position, the yarn lap is instead typically manipulated to the side of the enlarged diameter area of the take-up shaft by the machine operator while the shaft continues to rotate.
A number of such yarn laps on the take-up shaft may accumulate at each position before the open end spinning machine is shut down for other scheduled maintenance and all of the accumulated yarn laps may then be completely removed from the take-up shaft. Unfortunately, an accumulation of yarn laps may require that the open end spinning machine be operated at a reduced speed, thereby resulting in decreased production efficiency. In addition, the accumulated yarn laps present a potential fire hazard.
It is known that the tendency of the yarn to part may be reduced to thereby reduce the occurrence of yarn laps between scheduled maintenance activities. For example, the use of 100% cotton, rather than a blend, may reduce the likelihood of yarn breakage; however, it is the customer who ordinarily dictates the types of yarns to be produced. In addition, unsatisfactory attempts have been made to more precisely control the tension of the moving yarn to thereby reduce the number of yarn partings. Alternatively, the speed of the open end spinning machine may also be reduced to reduce fluctuations in yarn tension which may cause yarn partings.
Unfortunately, previous attempts to more precisely control yarn tension have proven unsuccessful and fail to address the problem of the accumulation of yarn laps resulting from parted yarns. In other words, controlling the yarn tension is not effective once a parting of the yarn has occurred. Reducing the speed of the spinning machine reduces production efficiency and is, thus, also undesirable. In addition, any proposed solution for preventing yarn laps would desirably take into account the substantial investment in open end spinning machines and, accordingly, a solution must be compatible with these existing machines. Moreover, the area of an open end spinning machine adjacent the enlarged diameter area of the rotating take-up shaft provides only very limited clearances between existing fixed and moving components.